1. Field of the Invention
The invention generally relates to a means for sensing the failure of a normal fluid flow through a conduit and more particularly a sensing means which is readily adaptable for the use in sensing the failure of cooling water flow to an internal combustion engine and levels of fuel in fuel tanks.
2. Description of the Prior Art
The cooling of engines by the continual flow of cool water therethrough is popular particularly in the cooling of marine engines because of the availability of water useable for this purpose.
The use of external water for the cooling of marine engines is not without its problems. In both ocean and fresh water vessels that have engines cooled in this manner there is a continual problem with debris being sucked against the input filter or debris actually being ingested into the external cooling water passages in the engine either terminating the water flow through the engine or impeding water flow to a degree that cooling is ineffective.
Presently engine temperature is monitored and when a predetermined temperature level occurs the operator of the boat, if he notices the increased level, immediately shuts down the engine to prevent overheating or the problem causing the overheating is located and corrected before the temperature reaches an engine damaging level. If the operator does not notice the overheating, the engine is eventually seriously damaged or destroyed by excessive heat or the external water pump impeller is damaged. Also, because the external water is used to cool the exhaust leaving the engine, the flexible exhaust pipe couplers can be damaged from overheating and could cause an onboard fire.
It has been found that the temperature sensing method normally employed is not always effective in preventing some damage to the engine. In some instances, the location of the temperature sensor does not give a true indication of the concerned areas of the engine and while the temperature of the engine indicated is not at an engine damaging level the parts of the engine's external cooling system may have already suffered some damage.
Another problem of concern to the vessel owner is pollution of the surrounding water when fueling the vessel, inadvertent spilling of fuel while filling onboard tanks results in water pollution and may result in heavy fines levied by the United States Coast Guard. The problem arises from the lack of adequate monitoring of the tank fuel level during filling. The fuel for filling is supplied from a dock side source at a tremendous flow rate and most ship board fuel level indicators even if properly operating will not properly react to this extreme fuel fill flow rate.
Single and multiple temperature sensors have been used to detect engine overheating with some success; however, there is a continuing need to improve the prevention of engine overheating.